In Vivo¹H‐NMR microimaging with respiratory triggering for monitoring adoptive immunotherapy of metastatic mouse lymphoma

Abstract

The metastatic ESb-MP murine lymphoma in DBA/2 mice has been used as a model for investigating metastatic disease and its cure by adoptive immunotherapy (ADI) as monitored by in vivo multislice spin-echo 1H NMR microimaging at 7 T. isoflurane inhalation anesthesia facilitated long measurement sessions, and respiratory gating with a fiber-optic sensor greatly reduced motional artifacts. With T2 weighting (TR = 2 s, TE = 30 ms) mean signal-to-noise ratios of 30 and 15 for kidney and liver, respectively, were achieved in 20 min (100-micron pixels, 1-mm slices, 25-mm field of view). Without the use of contrast agents, metastases with diameters > or = 0.3 mm in the imaged plane could be detected as hyperintense lesions in kidney (contrast ratio ca. 1.4) and liver (contrast ratio ca. 2) with a confidence level of > 98%. For the first time the complete eradication of late-stage macroscopic metastases by ADI could be demonstrated noninvasively by MRI.

Synchronisation strategies in T2-weighted MR imaging for detection of liver lesions: Application on a nude mouse model

“…Finally, the choice of the image contrast is limited by the fact that TR is controlled by T resp . Thus, image contrast is not freely controllable and TR is unsuitable for the required T2-weighted image contrast [17-19] especially at high magnetic field (4.7 T and more) due to the longitudinal relaxation time T1 increase with magnetic field.…”

Noninvasive In Vivo High-Resolution Magnetic Resonance Imaging of Atherosclerotic Lesions in Genetically Engineered Mice

“…This was the result of the intraperitoneal injection of pentobarbital, which produced low-amplitude motion in the thorax and abdomen as well as the tight constriction afforded by the mouse holder. A longer-lasting anesthetic, such as isoflurane inhalation anesthesia, 18 would allow longer imaging time. However, this anesthetic results in large-amplitude breathing motions in the mouse thorax and abdomen 18 and requires complicated respiratory gating methods 19 to obtain useful images.…”

“…A longer-lasting anesthetic, such as isoflurane inhalation anesthesia, 18 would allow longer imaging time. However, this anesthetic results in large-amplitude breathing motions in the mouse thorax and abdomen 18 and requires complicated respiratory gating methods 19 to obtain useful images.An in-plane spatial resolution of 97 m was adequate to visualize and quantify atherosclerotic lesion morphology in apoE-KO mice, as evidenced by the high correlation coefficients between the MR and histopathological measurements (Figure 4). The systematic overestimation of lesion size by MR compared with histopathological analysis is probably the result of specimen shrinkage that occurs during histological preparation and of volume-average effects (caused by the slice thickness and imaging plane orientation).…”

MRI and Characterization of Atherosclerotic Plaque

“…Carotid artery imaging after wire injury has also been performed in mice. 127 Respiratory and cardiac gating and continuous anesthetic administration will allow extended imaging to improve image quality 128,129 and will enable imaging of the thoracic aorta and aortic root. The aortic root is an attractive location for imaging because lesions develop earlier there than in the abdominal aorta.…”